Photoflash lamp



June 20, 1967 1 F. ANDERSON ETYAL 3,327,283

PHOTOFLASH LAMP Filed March 9, 1965 LESTER E ANDERSON WILLIAM C. FINK DONALD H. PFEFFERLE INVENTORS Wfw ATTORNEY United States Patent 3,327,283 PHOTOFLASH LAMP Lester F. Anderson, William C. Fink, and Donald H.

Pfefferle, Williamsport, Pa., assignors to Sylvania Electric Products Inc., a corporation of' Delaware Filed Mar. 9, 1965, Ser. No. 438,328 6 Claims. (Cl. 339-145) This invention relates to the manufacture of photoflash lamps and more particularly to photofiash lamps of the so-called subminiatu-re type, i.e., having a volume of about l ml. or less.

In the last decade many changes have been made in the direction of miniaturization of photoflash lamps. As the lamps became Ismaller and smaller, a num'ber of changes in lamp structure and the components thereof have been made. For example, each decrease in the overall size of the lamp envelope is usually accomplished by an increase in the concentration of the combustible and an increase in the pressure of the combustion-supporting gas.

Another change which has taken place in recent years has been the elimination of the metal base with which most photoflash lamp types have been provided over the years. One of the baseless lamps, known in the trade as a PF-L is illustrated in U.S. Patent 2,860,502 which issued on Nov. 18, 1958. This lamp has had wide acceptance in the European market. Another of these baseless lamps, known in the trade as an AG1, is illustrated in U.S. Patent 2,982,119 which issued on May 2, 1961. These two lamp types have what is generally termed a. pressed glass base.

The pressed glass base of the PF-l is characterized by a protuberance or tip which provides a suitable bearing surface for the application of a force thereagainst to facilitate ejection of a spent lamp from its socket or receptacle in associated photographic equipment. Much of the photographic equipment in Europe is designed to receive a PF-l lamp and is provided with ejection means operable in combination with the protu'berance or tip which characterizes the pressed glass base.

The pressed glass base of the AG1 is not provided with a protuberance or tip of the type with which the PF-1 is provided and thus it cannot be employed in photographic equipment designed to receive the PF-l. Since, in certain applications, the AG1 is a significantly better light source than the PF4, there is a substantial need and market for a photoflash lamp possessing the desirable AG1 characteristics and capable of being used in photographic equipment designed to receive the PF-l. This invention is concerned with providing such a lamp.

A lamp which has already been suggested for this purpose is characterized by a glass arbor projecting and depending from the bottom of the pressed glass base of an AG1. Effectuation of this structural change in an AG1 adds significantly to the time and cost yof the manufacturing operation because it involves the application of highly skilled glass Working techniques to insure the production of a product of reasonably high quality.

The principal object of this invention is to provide a photofiash lamp which possesses the desirable characteristics of an AG1 type photofiash lamp and is capable of being used in photographic equipment designed to receive a PF-l type photoflash lamp.

Another object of this invention is to provide such a lamp, the manufacture of which will require a minimum number of relatively mino-r changes in existing AG1 manufacturing equipment.

These and other objects, advantages and features are attained, in accordance with the principles of this invention, by providing an AG1 type photofiash lamp with a plastic cap of sufficient flexibility so that a snap-on fit on ICC the pressed glass base can be effected. In order to receive and cooperate with this plastic cap, a conventional commercial AG1 need 'be modified only by folding the lead-in wires extending therefrom up along the ends of the pressed glass base rather than shaping them into loops and pressing them against the sides of the pressed glass base as is normally done. The portions of the plastic cap which overlies the ends of the pressed glass base are cut away to expose segments of the lead-in wires so that electrical contact can be made therewith in a socket or receptacle of the photographic equipment with which the lamp is to be employed. The bottom of the plastic cap is provided with a depending, substantially cylindrical projection for facilitating the ejection of a spent lamp from the photographic equipment.

In the accompanying drawing, FIGURE 1 is an exploded perspective view of a specific embodiment of a photoflash lamp and a plastic cap therefor in accordance with this invention.

FIGURE 2 is a perspective View of the lamp-cap assembly of FIGURE l in a completely assembled state.

FIGURE 3 is a fragmentary sectional view of the assembled lamp and cap of FIG. 2, taken along the lines 3-3 thereof.

In the specific embodiment of the invention illustrated in the accompanying drawing, lamp 1 comprises an hermetically sealed envelope 2 characterized by an exhaust tip 4 at one end thereof and a pressed glass base 6 having transverse grooves 7 formed therein at the other end thereof. Lead-in wires 8 and 10 are sealed in the base 6 intermediate their ends, the outer ends defining electrical contacts as will be described more fully below and the inner ends supporting an ignition system not shown. The ignition system comprises the usual filament bridging the lead-in wires near the inner ends thereof and beads of igniter on the inner ends of the lead-in wires. The envelope 2 is provided with a filling of combustion-supporting gas, such as oxygen for example, at a pressure 0f several atmospheres, and a body of combustible 12 such as shredded zirconium foil for example.

The base 6 of the lamp 1 is provided with a plastic cap 14 of polyethylene, polypropylene, polyvinylchloride or the like, characterized by a flexibility sufficient to provide a snap-0n fit. The cap 14 is characterized by a body member 16, somewhat oblong in shape, a collar 18 about the upper portion of the body member, and a substantially cylindrical projection defining a pin 2t) depending from the bottom of the body member. The sides of the body member 16 are provided with flats 16a and the ends are provided with elongated slots 16b. The inner faces of the sides of the body member 16 are provided with transverse projections or ridges 16C.

In preparation for the assembling of the lamp 1 and the cap 14, each of the lead-in wires 8 and 10 is bent back along the adjacent end of the pressed glass 'base 6 of the lamp. The cap 14 is then slipped over the base 6 with the lead-in wires 8 and 10 so disposed, until the components are united as shown in FIGS. 2 and 3. As shown therein, segments of the lead-in wires 8 and 10 lie within the elongated slots 161: in the ends of the body member of the cap. These exposed segments of lead-in wires 8 and 10 define electrical contacts for engagement with suitable cooperating electrical contacts in the photographic equipment with which the capped lamp is designed to be employed. As shown in FIG. 3, the lead-in wires 8 and 10 are snugly retained against the neck of the lamp envelope 2 by the collar 18 of the cap 14. As the cap 14 is fitted on the base 6, the ridges 16C on the inner faces of the sides of the body member 16 snap into the transverse grooves 7 formed on opposite sides of the pressed glass base, thus securing the cap to the lamp. The substantially cylindrical projection depending from the bottom of the body member 16 of the cap 14 defines an ejection pin 20. Actuation of a suitable mechanism, within the photographic equipment with which the capped lamp is employed, effects the application of a force on the end of the pin 20 suflicient to dislodge the capped lamp from its socket or receptacle in the photographic equipment. This operation is performed to effect the discharge of a spent lamp.

What we claim is:

1. A photofiash lamp comprising:

terminal press defining a base at one end thereof; ternal press defining a base at one end thereof:

a pair of lead-in wires sealed in said base and extending therefrom, said extensions being bent back along opposite ends of said base;

and a plastic cap fitted on said `base and against said wires, said cap having a pair of elongated slots formed therein, said slots being in register with said lead-in wires, whereby the segments of said lead-in wires so exposed define electrical cont-act members.

2. A photofiash lamp comprising:

an hermetically sealed glass envelope having an external press defining a base at one end thereof;

a pair of lead-in wires sealed in said base and extending therefrom, said extensions being bent back along opposite ends of said base;

and a plastic cap fitted on said base, said cap having a collar engaging said lead-in wires near the free ends thereof and securely retaining said lead-in wires against the neck of said enevelope, said cap also having a pair of elongated slots formed therein, said slots being in register with said lead-in wires, whereby the segments of said lead-in wires so exposed define electrical contact members.

3. A photoffash lamp comprising:

an hermetically sealed glass envelope having an external press defining a base at one end thereof;

a pair of lead-in wires sealed in said base and extending therefrom, said extensions being bent Iback along opposite ends of said base;

and a plastic cap fitted on said base and against said wires, said cap having a pair of elongated slots formed therein, said slots being in register with said lead-in wires, whereby the segments of said lead-in wires so exposed define electrical contact members, and said cap also having a pin depending from the bottom thereof.

4. A photoash lamp comprising:

an hermetically sealed glass envelope having an external press defining a base at one end thereof;

a pair of lead-in wires sealed in said base and extending therefrom, said extensions being bent back along opposite ends of said base;

l against the neck of said envelope, said cap also having a pair of elongated slots formed therein, said slots being in register with said lead-in wires, whereby the segments of said lead-in wires so exposed define electrical contact members, and said cap also having a pin depending from the bottom thereof.

5. A photoffash lamp comprising:

an hermetically sealed glass envelope having an external press defining a base at one end thereof, said base having transverse grooves formed in opposite sides thereof;

a pair of lead-in wires sealed in said base and extending therefrom, said extensions being bent back along opposite ends of said base;

and a plastic cap fitted on said base, said cap having a pair of elongated slots formed in the ends thereof, said slots being in register with said lead-in wires, whereby the segments of said lead-in wires so exposed define electrical contact members, and said cap also having transverse ridges formed on the inner faces of the sides thereof, said ridges interlocking with said grooves in said base to thereby retain said cap on said enevelope.

6. A photollash larnp comprising:

an hermetically sealed glass envelope having an external press defining a base at one end thereof, said base having transverse grooves formed in opposite sides thereof;

a pair of lead-in wires sealed in said base and extending therefrom, said extensions being 'bent back along opposite ends of said base;

and a plastic Cap fitted on said base, said cap having a collar engaging said lead-in wires near the free ends thereof and securely retaining said lead-in wires against the neck of said envelope, said cap also having a pair of elongated slots formed in the ends thereof, said slots being in register with said leadin wires, whereby the segments of said lead-in wires so exposed define electrical contact members, and said cap also having transverse ridges formed on the inner faces of the sides thereof, said ridges interlocking with said grooves in said base to thereby retain said cap on said envelope.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 6/1965 Great Britain.

and a plastic cap fitted on said base, said cap having a collar engaging said lead-in wires near the free ends thereof and securely retaining said lead-in wires Examiner. 

1. A PHOTOFLASH LAMP COMPRISING: TERMINAL PRESS DEFINING A BASE AT ONE END THEREOF: TERNAL PRESS DEFINING A BASE AT ONE END THEREOF: A PAIR OF LEAD-IN WIRES SEALED IN SAID BASE AND EXTENDING THEREFROM, SAID EXTENSIONS BEING BENT BACK ALONG OPPOSITE ENDS OF SAID BASE; AND A PLASTIC CAP FITTED ON SAID BASE AND AGAINST SAID WIRES, SAID CAP HAVING A PAIR OF ELONGATED SLOTS FORMED THEREIN, SAID SLOTS BEING IN REGISTER WITH SAID LEAD-IN WIRES, WHEREBY THE SEGMENTS OF SAID LEAD-IN WIRES SO EXPOSED DEFINE ELECTRICAL CONTACT MEMBERS. 